1. Technical Field
The present disclosure relates to a control device and a control method for a vehicle that transmit the torque output from a drive power source to a drive wheel.
2. Description of Related Art
A drive device of a hybrid vehicle having an engine, a first motor, and a second motor as drive power sources is described in Japanese Patent Application Publication No. 2009-120043 (JP 2009-120043 A). The drive device of the hybrid vehicle described in this JP 2009-120043 A is equipped with a power split mechanism that transmits the output torque of the engine and the first motor to a drive wheel side. The power split mechanism is constituted by a single pinion type planetary gear mechanism. The engine is coupled to a carrier of the planetary gear mechanism, the first motor is coupled to a sun gear, and an output member that transmits power to a drive wheel is coupled to a ring gear. In this hybrid vehicle, driving can be performed by selectively setting an electric driving mode in which the power output from at least one of the first motor and the second motor in a state where the engine is stopped is transmitted to the drive wheel, a regenerative driving mode in which at least any of the first motor or the second motor is made to function as a generator, and an engine driving mode in which the power output from the engine is transmitted to the drive wheel. Additionally, the drive device of the hybrid vehicle described in this JP-2009-120043 A is equipped with an engagement type clutch (locking mechanism) for stopping and fixing the rotation of the engine in the above electric driving mode. The engagement type clutch is disposed inside a case that houses the first motor, the second motor, the power split mechanism, and the like.
Additionally, a transmission for a vehicle equipped with a shifting mechanism to which engine torque is input via an input shaft of the transmission, and a torque limiter disposed between the input shaft of the transmission and the engine is described in International Publication No. WO2013/140527. The torque limiter is configured so as to allow torque to be transmitted between the input shaft of the transmission and an engine output shaft and inhibit a larger surplus torque than a predetermined torque from being transmitted between the input shaft of the transmissions and the engine output shaft. The transmission for a vehicle described in this International Publication No. WO2013/140527 is mounted on the hybrid vehicle having the engine, the first motor, and the second motor as the drive power sources, similar to JP 2009-120043 A. A one-way clutch or a dog clutch is provided as an engaging mechanism that allows the normal rotation of the engine output shaft and prevents the reverse rotation of the engine output shaft.
According to the drive device of the hybrid vehicle described in the above JP 2009-120043 A, when motor driving is performed in the electric driving mode, the drag loss of the engine during the motor driving can be reduced by actuating the locking mechanism to stop (lock) the rotation of the engine. Additionally, in a case where the motor driving is performed with high output by the output torque of both the first motor and the second motor, the output torque of the first motor can be efficiently transmitted to the output member via the power split mechanism in which the rotation of the carrier is locked, together with the engine. In the drive device of the hybrid vehicle described in JP 2009-120043 A, for example, if the dog clutch that is described in the above International Publication No. WO2013-140527 is applied, the input of the excessive torque in the power transmission path between the drive wheel and the engine can be suppressed.